Since your dryer is running,the thermal fuse referenced above is OK.The Thermal cut out comes in a kit with the Hi limit thermostat and may be bad.If either the thermostat or thermal cut out are bad,change them both.As mentioned above,the heating element may be broken.All these parts can be checked witha voltage meter set for ohms or continuity.http://www.appliancepartspros.com/whirlpool-thermal-cut-off-279769-ap3094224.html